Method for repairing existing wood piling



J. K. KERSHAW METHOD FOR REPAIRING EXISTING WOOD FILING Sept. 3, 1935.

Filed April 20, 1954 VI m John Knox Kem/zaw INVENTOR Patented Sept. 3, 1935 4 Claims. (01. 61-53) ll/1y" invention relates to a novel method of utilizing concrete pile'sections to repair piling. -My inve1 ition, being more particularly con- H cerned'withthe treatmentof wood piles to avoid "5 the necessity for their replacement with new piles; it is necessary to point out the existing practice'withreierence to'the protection,repair and maintenance'of wood piles and the disadvantage respectbf same in order that the advantages of my inventionmay be clearly understood.

,Anordinary 65 foot-wood pile, set in twenty "feetoi water, will have approximately thirty feet driven'into the mud and fifteen feet exposed above the mean high water level; Of course such a pile is merelytypical; but it will serve for illustrative purposes, and, according to the charhacter of thewoodand its condition, itwill have lifefiof from three to five years by which time the twenty foot stretch between the mudline and the meanhigh water'level will have beensub- .jected tomarineinsect attack and weakened'beyondfithe point of usefulness. Under such con- 1 ditions, the generally employed method is to abandonthe pile and drive a new-wood pile into Yposition, alongside it to take itsload. This involvesithe useof a pile driver and necessitates ,clearin'g 'awaybf dock or trestle work overhead s hat the pile driver may be used. r

Thecost of'such, a "replacement pile, includ-, ing labor and, mechanismior its; replacement, will run approximately $2.00 per foot of'pile and itwillbeobvious that since wood piles must be 'depreciated at the rate of lirom 33 to;% per ammmthere results a fixed maintenance jchargeof from ,66 to .40, per foot of pile per annumf in orderto reduce this high cost of maintenance? attempts have been made to protectwith a 'concrete jacket the section of the pile exposed to the water, concrete being a substance batable whether their cost is justified by the reduction of maintenance charges. The pile section below the mud line being prac- "tically imperis hab le and the upper pile section 7 above the mean water line being where it can be protected by painting or treatment, it has been ,at, present regarded as having the highest re- -ierred form is illustrated, u

UNITED STATES PATENT OFFICE \METHOD For; REPAIRING EXISTING WOOD PILIN G proposed to produce a new composite pile comprising a lower wooden pile end, an intermediate re1nforced concrete pile section, and an 'upper wooden pile section, the composite pile being assembled and driven into place so as to leave only the concrete section exposed betweenthe mud .line and the mean high water level. It is difiicult to drive such a sectional pile into place and there is always the possibility of the intermediate concrete section being injured or damaged byjthe" pile driver blows. While this proposal may reduce the maintenance cost for new piling, up to the present time no feasible method has been found to salvage the sound portions of defective wooden piles in place and restore such piles without the use ofa pile'driver and without leaving .any

perishable part exposedto marine insect attack. The object of my invention-briefly stated,

therefore, is to devise a means whereby when existing wood piling has deteriorated beyond the r point of usefulness, those portions of the piles which are still soundand represent approximate ly 70% of the pile,-can be saved and the piling restored without disturbing the superstructure "which it supports or necessitating the use of any? pile driving equipment. r

I" propose to accomplish the foregoing object by cutting away the damaged intermediate pile section which will be joined in a novel :man-

ner"to,a,nd be supported by, the lowerembeddedrr end of the old pile and which will be suitably spliced to the upper end of the old pile whereby the old wood .pile is reestablished in its load supporting functions by the interposition of an intermediate reinforced concrete section which ism of permanent durability in that it will not be attacked by marine insects, and thereforean old wooden pile, thus repaired, will have practically indefinite life. a i i 1 My invention further comprises the novel man-(i ner in which the concrete splice section is cou- 1 pled to the wooden pile sections and to the manner in which it is installed in position, all of which will be more clearly understood by reference *tothe accompanying drawing wherein thei:

manner of practicing my invention in its pre- Fig. 1 shows an old wood pile with itsintermediate defective portion, that has been cut away,

shown in dotted lines.

Fig; 2 shows the process of restoration of the 'pile of Fig. 1 by the insertion of the concrete splice pile section, the lower end of the wood pile being broken away.

Fig. 3 shows the pile of Fig. 1 completely restored with its reinforced concrete splice sections shown in vertical central cross section.

Fig. 4 is an enlarged cross sectional view taken on the line IVIV of Fig. 3.

Fig. Sis a corresponding view taken on the line V-V of Fig. 3.

Similar reference numerals refer to similar parts throughout the drawing.

In the embodiment of my invention illustrated in the accompanying drawing, I show in Fig. 1 a typical wood pile comprising a top portion 5 above the water level, an intermediate portion 6, and a lower end I driven into the mud. It is tied to a superstructure 8 by splice irons 9 and braced thereto by the diagonal braces Hi. It i's'connected to the otherpiles by the horizontal 'woodbracing ll tied to the pile by upper and lower bolts l2.

TheportionB of the pile above the mean high water-line, indicated by the dotted line marked H. W., is shown to be sound and serviceable. :The'lower end i of the pile below the mud line is always sound and perfectly preserved. Only that intermediate section 6 of the pile that is =exposed to the water between the mud line and the =M. H. -W. level has been attacked and practicallydestroyedby-marine insects. Such a de- -fective1pile under present practice would be con- *demned and anew pile would be driven to replace'it.

xMy methodfor the restoration of such a pile is" illustrated in Figs. 2 and 3. It will be noted Fthepile section-6 has been cut away near the mud :line and overhead about a foot and a half above mthemean high water line, the horizontal bracing having been disconnected or'if necessary detached, to permit this. The'intermediate section 6 of the pile is then discarded and a precast .sreinforcedponcrete splice pile section I3 is pro-- ;-vided. This splice pile section has at its-lower end an enlarged base l4 recessed to provide a chamber l5 adapted to telescope over the upper end -of'the pile section 1 leftin the mud and to make a fairly close fit about it. The length of this splice pile section is-such that, when it has beentelescoped into position over the wood pile section-I, its-upper end will abut or fit snugly against the upperpile section 5, thus replacingthe cut away portion 6 of the pile.

Themanner ofplacing the splice pile section is important and will now be described.

The upper-wood pile section 5 has its-braces 1-0 and i I and connections 9 to the superstructure loosened or removed suificiently for it to be displaced and allow the precast concrete splice pile'section to' be lowered into position over the bottom. pile section 1. The diver, who made the "'saw cut at the mud line guides the chambered base 14 of the precast splice pile section into position over the upper end of the wood pile section 'l'and'then places on top of the pile l a frangible water-proof package I6 containing liq- =uid' grout, tar or any suitable filler.

-Anair pipe connection I! from the divers outfit is utilized to introduce air into the chamber '15 in the precast pile, if necessary, to displace the water therefrom. The precast pile is then "lowered into position over pile l and water jet .apipes 23"are used by the diver as a convenient means for displacing the sand around the base l4 of the precast pile so that it can be sunk into the mud until it comes to rest on the wood pile section 1. As the precast pile is thus lowered, a portion of the air will be displaced by the pile i and finally the pile l3 will compress and burst the package I 6 of filler effecting its discharge into the upper portion of the chamber l5 and causing it to be forced downwardly as the precast pile settled. In thus settling, the filler I 8 follows the air that has been displaced and seals the clearance between the wood pile 1 and the chamber walls [5 and will exude from the bottom, thus effectively sealing this joint. Any voids in the joint will remain filled with air that will prevent access of water to the pile I and the base of the precast pile will telescope deeply enough'into the mud to maintain the seal against access of water to the enclosed wood pile section I. The precast piles upper end is brought into alignment with the wood pile section 5 and a form having been :placed about this joint, a reinforced concrete splice sleeve I9 is cast "about the joint with the bolts l2 in place, a hole-having been provided in the=upper end of themecast pile to receive the lower bolt.

The horizontal bracing H is then-tied tothese bolts i2, the diagonal bracingifl is.reinstated,.the irons 9 are reconnected-and we-have the completely restored pile with its component vparts 5, l3 and 1 ready to render long serviceas it .will

be free from attack-bymarinelife.

the old Wooden pile section belowthe mudline which is imperishable. The precast concrete section l3 that alone will .beexposed to the water .is likewise practicallyimperishable and theupper wood pile section 5 will behi'ghlydurableflbut should it deteriorate, a short replacement section can be readily dropped in place withoutlm'aterial expense or disarrangement of the superstructure.

The maintenance chargesnare thus practically eliminated and the repair of old woodpiling can be thus accomplished at a fraction of the. costof replacing it with new wood piles.

Preferably the lowerv end of thebase is' tapered to facilitate its penetration into .the mud. [The body I3 of. the precast pile is. hexagonal in shape with longitudinal and circumferential reinforcing elements 20 and'f2i, which aretypical vofany suitable reinforcement, provided therein.

Preferably the splice sleeve II is itself provided with a suitable reinforcement 22.

While I have shown myinvention in but one form, it will be obvious to those skilled in'the art that it isnot so limited, butis susceptible of various changes and modifications, without departing from the spirit thereof, .andI desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set'forth in the appended claims.

What I claim is:

1. The herein described method for .the repair of wood piling, which comprises cutting away the intermediate defective portion of the pile between the mud lineand solid-wood above the mean high water level, interposing a concrete pile section I to replace the cutaway wood pile section, provida 'base extension on the concrete section shaped to telescope over the upper end of the lower wood pile section left in place and lowering the concrete section into position onto the lower wood pile section, and connecting the upper end of the concrete section to the upper portion of. the wood pile.

2. The herein described method for the repair of wood piling, which comprises cutting away the intermediate defective portion of the pile between the mud line and solid wood above the mean high water level, interposing a concrete pile section to replace the cut away wood pile section, providing a base extensipn on the concrete section shaped to telescope over the upper end of the lower wood section left in place introducing air in the chamber in the base of the concrete section to displace the water therefrom and using water jets to lower the concrete section into position onto the lower wood pile section, and connecting the upper end of r the concrete section to the upper portion of the wood pile.

3. The herein described method for the repair of wood piling, which comprises cutting away the intermediate defective portion of the pile between the mud line and solid wood above the mean high water level, interposing a concrete pile section to replace the cut away wood pile section, providing a base extension on the concrete section shaped to telescope over the upper end of the lower wood pile section left in place, placing a frangible package of a liquid filler in position between the bottom Wood pile section and the concrete section and lowering the concrete section to rest on the lower wood pile section, causing the fracture of the filler package and the sealing thereby of. the voids in the telescoped joint between the wood and concrete pile sections, and joining the upper end of the concrete pile section to the upper remaining portion of the wood pile.

4. The herein described method for the repair of old wood piling, which comprises cutting away the existing wooden pile adjacent to the mud line, providing a precast reinforced concrete replacement pile section, providing a portion on said pile section to telescope over the cut away'lower end of the wood pile and to project substantially below the mud line, interposing air in said recessed end of the precast pile to free it of water and placing a fluid filler in a frangible container on the upper end of the lower wood pile section, and lowering the precast pile section into position on said lower wood pile section so as tocrush the container and force the filler under pressure to exude from the joint between the concrete and wood pile sections, and connecting the upper end of the concrete pile section overhead to the superstructure.

JOHN KNOX KERSHAW. 

